xnodeset.java

java1.6众多例子参考

/*
 * Copyright 1999-2004 The Apache Software Foundation.
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */
/*
 * $Id: XNodeSet.java,v 1.2.4.2 2005/09/14 20:34:45 jeffsuttor Exp $
 */
package com.sun.org.apache.xpath.internal.objects;

import com.sun.org.apache.xml.internal.dtm.DTM;
import com.sun.org.apache.xml.internal.dtm.DTMIterator;
import com.sun.org.apache.xml.internal.dtm.DTMManager;
import com.sun.org.apache.xml.internal.utils.XMLString;
import com.sun.org.apache.xpath.internal.NodeSetDTM;
import com.sun.org.apache.xpath.internal.axes.NodeSequence;

import org.w3c.dom.NodeList;
import org.w3c.dom.traversal.NodeIterator;

/**
 * This class represents an XPath nodeset object, and is capable of
 * converting the nodeset to other types, such as a string.
 * @xsl.usage general
 */
public class XNodeSet extends NodeSequence
{  
    static final long serialVersionUID = 1916026368035639667L;
  /**
   * Default constructor for derived objects.
   */
  protected XNodeSet()
  {
  }

  /**
   * Construct a XNodeSet object.
   *
   * @param val Value of the XNodeSet object
   */
  public XNodeSet(DTMIterator val)
  {
  	super();
  	if(val instanceof XNodeSet)
  	{
	    setIter(((XNodeSet)val).m_iter);
	    m_dtmMgr = ((XNodeSet)val).m_dtmMgr;
	    m_last = ((XNodeSet)val).m_last;
	    if(!((XNodeSet)val).hasCache())
	    	((XNodeSet)val).setShouldCacheNodes(true);
	    m_obj = ((XNodeSet)val).m_obj;
  	}
  	else
    	setIter(val);
  }
  
  /**
   * Construct a XNodeSet object.
   *
   * @param val Value of the XNodeSet object
   */
  public XNodeSet(XNodeSet val)
  {
  	super();
    setIter(val.m_iter);
    m_dtmMgr = val.m_dtmMgr;
    m_last = val.m_last;
    if(!val.hasCache())
    	val.setShouldCacheNodes(true);
    m_obj = val.m_obj;
  }


  /**
   * Construct an empty XNodeSet object.  This is used to create a mutable 
   * nodeset to which random nodes may be added.
   */
  public XNodeSet(DTMManager dtmMgr) 
  {
     this(DTM.NULL,dtmMgr);
  }

  /**
   * Construct a XNodeSet object for one node.
   *
   * @param n Node to add to the new XNodeSet object
   */
  public XNodeSet(int n, DTMManager dtmMgr)
  {

    super(new NodeSetDTM(dtmMgr));
    m_dtmMgr = dtmMgr;

    if (DTM.NULL != n)
    {
      ((NodeSetDTM) m_obj).addNode(n);
      m_last = 1;
    }
    else
    	m_last = 0;
  }

  /**
   * Tell that this is a CLASS_NODESET.
   *
   * @return type CLASS_NODESET
   */
  public int getType()
  {
    return CLASS_NODESET;
  }

  /**
   * Given a request type, return the equivalent string.
   * For diagnostic purposes.
   *
   * @return type string "#NODESET"
   */
  public String getTypeString()
  {
    return "#NODESET";
  }

  /**
   * Get numeric value of the string conversion from a single node.
   *
   * @param n Node to convert
   *
   * @return numeric value of the string conversion from a single node.
   */
  public double getNumberFromNode(int n)
  {
    XMLString xstr = m_dtmMgr.getDTM(n).getStringValue(n);
    return xstr.toDouble();
  }

  /**
   * Cast result object to a number.
   *
   * @return numeric value of the string conversion from the 
   * next node in the NodeSetDTM, or NAN if no node was found
   */
  public double num()
  {

    int node = item(0);
    return (node != DTM.NULL) ? getNumberFromNode(node) : Double.NaN;
  }
  
  /**
   * Cast result object to a number, but allow side effects, such as the 
   * incrementing of an iterator.
   *
   * @return numeric value of the string conversion from the 
   * next node in the NodeSetDTM, or NAN if no node was found
   */
  public double numWithSideEffects()
  {
    int node = nextNode();

    return (node != DTM.NULL) ? getNumberFromNode(node) : Double.NaN;
  }


  /**
   * Cast result object to a boolean.
   *
   * @return True if there is a next node in the nodeset
   */
  public boolean bool()
  {
    return (item(0) != DTM.NULL);
  }
  
  /**
   * Cast result object to a boolean, but allow side effects, such as the 
   * incrementing of an iterator.
   *
   * @return True if there is a next node in the nodeset
   */
  public boolean boolWithSideEffects()
  {
    return (nextNode() != DTM.NULL);
  }

  
  /**
   * Get the string conversion from a single node.
   *
   * @param n Node to convert
   *
   * @return the string conversion from a single node.
   */
  public XMLString getStringFromNode(int n)
  {
    // %OPT%
    // I guess we'll have to get a static instance of the DTM manager...
    if(DTM.NULL != n)
    {
      return m_dtmMgr.getDTM(n).getStringValue(n);
    }
    else
    {
      return com.sun.org.apache.xpath.internal.objects.XString.EMPTYSTRING;
    }
  }
  
  /**
   * Directly call the
   * characters method on the passed ContentHandler for the
   * string-value. Multiple calls to the
   * ContentHandler's characters methods may well occur for a single call to
   * this method.
   *
   * @param ch A non-null reference to a ContentHandler.
   *
   * @throws org.xml.sax.SAXException
   */
  public void dispatchCharactersEvents(org.xml.sax.ContentHandler ch)
          throws org.xml.sax.SAXException
  {
    int node = item(0);
	
    if(node != DTM.NULL)
    {
      m_dtmMgr.getDTM(node).dispatchCharactersEvents(node, ch, false);
    }
    
  }
  
  /**
   * Cast result object to an XMLString.
   *
   * @return The document fragment node data or the empty string. 
   */
  public XMLString xstr()
  {
    int node = item(0);
    return (node != DTM.NULL) ? getStringFromNode(node) : XString.EMPTYSTRING;
  }
  
  /**
   * Cast result object to a string.
   *
   * @return The string this wraps or the empty string if null
   */
  public void appendToFsb(com.sun.org.apache.xml.internal.utils.FastStringBuffer fsb)
  {
    XString xstring = (XString)xstr();
    xstring.appendToFsb(fsb);
  }
  

  /**
   * Cast result object to a string.
   *
   * @return the string conversion from the next node in the nodeset
   * or "" if there is no next node
   */
  public String str()
  {
    int node = item(0);
    return (node != DTM.NULL) ? getStringFromNode(node).toString() : "";   
  }
  
  /**
   * Return a java object that's closest to the representation
   * that should be handed to an extension.
   *
   * @return The object that this class wraps
   */
  public Object object()
  {
    if(null == m_obj)
    	return this;
    else
    	return m_obj;
  }

  // %REVIEW%
  // hmmm...
//  /**
//   * Cast result object to a result tree fragment.
//   *
//   * @param support The XPath context to use for the conversion 
//   *
//   * @return the nodeset as a result tree fragment.
//   */
//  public DocumentFragment rtree(XPathContext support)
//  {
//    DocumentBuilderFactory dbf = DocumentBuilderFactory.newInstance();
//    DocumentBuilder db = dbf.newDocumentBuilder();
//    Document myDoc = db.newDocument();
//    
//    DocumentFragment docFrag = myDoc.createDocumentFragment();
//
//    DTMIterator nl = iter();
//    int node;
//
//    while (DTM.NULL != (node = nl.nextNode()))
//    {
//      frag.appendChild(node, true, true);
//    }
//
//    return frag.getDocument();
//  }

  /**
   * Cast result object to a nodelist.
   *
   * @return a NodeIterator.
   *
   * @throws javax.xml.transform.TransformerException
   */
  public NodeIterator nodeset() throws javax.xml.transform.TransformerException
  {
    return new com.sun.org.apache.xml.internal.dtm.ref.DTMNodeIterator(iter());
  }
  
  /**
   * Cast result object to a nodelist.
   *
   * @return a NodeList.
   *
   * @throws javax.xml.transform.TransformerException
   */
  public NodeList nodelist() throws javax.xml.transform.TransformerException
  {
    com.sun.org.apache.xml.internal.dtm.ref.DTMNodeList nodelist = new com.sun.org.apache.xml.internal.dtm.ref.DTMNodeList(this);
    // Creating a DTMNodeList has the side-effect that it will create a clone
    // XNodeSet with cache and run m_iter to the end. You cannot get any node
    // from m_iter after this call. As a fix, we call SetVector() on the clone's 
    // cache. See Bugzilla 14406.
    XNodeSet clone = (XNodeSet)nodelist.getDTMIterator();
    SetVector(clone.getVector());
    return nodelist;
  }

  
//  /**
//   * Return a java object that's closest to the representation
//   * that should be handed to an extension.
//   *
//   * @return The object that this class wraps
//   */
//  public Object object()
//  {
//    return new com.sun.org.apache.xml.internal.dtm.ref.DTMNodeList(iter());
//  }

  /**
   * Return the iterator without cloning, etc.
   */
  public DTMIterator iterRaw()
  {
    return this;
  }
  
  public void release(DTMIterator iter)
  {
  }
  
  /**
   * Cast result object to a nodelist.
   *
   * @return The nodeset as a nodelist
   */
  public DTMIterator iter()
  {
    try
    {
    	if(hasCache())
      		return cloneWithReset();
      	else
      		return this; // don't bother to clone... won't do any good!
    }
    catch (CloneNotSupportedException cnse)
    {
      throw new RuntimeException(cnse.getMessage());
    }
  }
  
  /**
   * Get a fresh copy of the object.  For use with variables.
   *
   * @return A fresh nodelist.
   */
  public XObject getFresh()
  {
    try
    {
    	if(hasCache())
      		return (XObject)cloneWithReset();
      	else
      		return this; // don't bother to clone... won't do any good!
    }
    catch (CloneNotSupportedException cnse)
    {
      throw new RuntimeException(cnse.getMessage());
    }
  }

  /**
   * Cast result object to a mutableNodeset.
   *
   * @return The nodeset as a mutableNodeset
   */
  public NodeSetDTM mutableNodeset()
  {
    NodeSetDTM mnl;

    if(m_obj instanceof NodeSetDTM)
    {
      mnl = (NodeSetDTM) m_obj;
    }
    else
    {
      mnl = new NodeSetDTM(iter());
      m_obj = mnl;
      setCurrentPos(0);
    }

    return mnl;
  }

  /** Less than comparator         */
  static final LessThanComparator S_LT = new LessThanComparator();

  /** Less than or equal comparator          */
  static final LessThanOrEqualComparator S_LTE = new LessThanOrEqualComparator();

  /** Greater than comparator         */
  static final GreaterThanComparator S_GT = new GreaterThanComparator();

  /** Greater than or equal comparator          */
  static final GreaterThanOrEqualComparator S_GTE =
    new GreaterThanOrEqualComparator();

  /** Equal comparator         */
  static final EqualComparator S_EQ = new EqualComparator();

  /** Not equal comparator         */
  static final NotEqualComparator S_NEQ = new NotEqualComparator();

  /**
   * Tell if one object is less than the other.
   *
   * @param obj2 Object to compare this nodeset to
   * @param comparator Comparator to use
   *
   * @return See the comments below for each object type comparison 
   *
   * @throws javax.xml.transform.TransformerException
   */
  public boolean compare(XObject obj2, Comparator comparator)
          throws javax.xml.transform.TransformerException
  {

    boolean result = false;
    int type = obj2.getType();

    if (XObject.CLASS_NODESET == type)
    {
      // %OPT% This should be XMLString based instead of string based...

      // From http://www.w3.org/TR/xpath: 
      // If both objects to be compared are node-sets, then the comparison 
      // will be true if and only if there is a node in the first node-set 
      // and a node in the second node-set such that the result of performing 
      // the comparison on the string-values of the two nodes is true.
      // Note this little gem from the draft:
      // NOTE: If $x is bound to a node-set, then $x="foo"